Proven Alternative to Weld Overlay in a Corroded Fractionator Tower

Corrosion Emergency

Built in the late 1970s, this 126,000-bpd refinery is one of Saudi Arabia’s oldest grassroots refineries. It comes as no surprise that some of its existing equipment is now approaching the end of its life.

During a 2014 shutdown, the fractionator tower was found to be suffering pitting corrosion and required urgent protection to prevent the loss of integrity and a need for replacement. The operator considered two alternatives: 1) Weld overlay/ weld build up 2) IGS HVTS (High Velocity Thermal Spray). Weld overlay would have come with a requirement for tower stabilization and PWHT making it a less practical choice in terms of cost and time (with this being an emergency).


Unexpected pitting corrosion in a section of the fractionator tower at a Saudi Arabia refinery.



IGS HVTS was applied in 2014 to a 89m² area, from tray 47 to 56. In 2017, following positive inspection results, the scope has been extended to include the manway, lid and internals beneath tray 47, a 44m² area. In 2020, both IGS HVTS applications have been inspected and found to be in excellent condition.

IGS HVTS Experience

“Thermal spray” is not new. IGS HVTS, however, is a different class of technology. The material, its conveyancing technology and the application procedure have all been optimized over some decades to make IGS HVTS fit for mission-critical equipment protection. IGS HVTS has been approved by the oil company operating this and other refineries in the region prior to 2014. As a result, this technology has been chosen to address the corrosion problem in the fractionator tower.


hvts inside a vessel or drum
tower or column

IGS HVTS Application in 2014

The HVTS application was completed in 84 hours. An additional 72 hours were utilized to set up, pull in and out of the vessel as well as complete other tasks such as blow down, inspection and sealing. A total of 10 days were spent on site, working within the critical path of the shutdown.


Extended Scope in 2017

HVTS cladding applied in 2014 was inspected and found to be in good condition. Additional scope was identified during the initial outage inspections. Working together with the shutdown team IGS mobilized equipment and personnel, completing the expanded scope within the required shutdown timeframe.

2020 Inspection

The entire 132m2 area cladded with HVTS was inspected in 2020. The IGS HVTS cladding was found to be in good condition with minimal to no thickness loss and ready for service.



Thermal spray